William Henry Parker III (June 21, 1905 – July 16, 1966) was the police chief of the Los Angeles Police Department (LAPD) and has been called "Los Angeles' greatest and most controversial chief of police".[1] He was the longest serving police chief and served on the force 39 years. The former headquarters for the LAPD, the Parker Center, was named after him.

Parker became police chief on August 9, 1950, and is credited with transforming the LAPD into a world-renowned law enforcement agency. The department that he took over in 1950 was notoriously corrupt.[3] Seeing the old ward peacekeeping politics, with its heavy involvement by partisan groups in the police department and commingling of political circles with vice and corruption on the streets, led him to conclude that a different organized police force was necessary to keep the peace.

Parker's experience with military public relations in World War II was used to develop an effective media relations strategy for the police department.[citation needed] Thanks to shows such as Dragnet[4] and a steady stream of good publicity from local newspapers, he was highly admired nationwide. Parker was a guest on the television program What's My Line? on August 21, 1955.

Under Parker's early term, the Los Angeles Police Department initiated a more professionalized force which institutionalized officers into an environment that was more answerable to administrative oversight than political representatives. Included in this change was a standardized police academy, more proactive policing methods, practices very similar to military peacekeeping methods to which he was exposed during the war.[1]

Another aspect of changes initiated by Parker which changed the police force from one of a walking peace-force to a more militarized mobile response force, was a reduction in the size of the police force, in relation to the population. The term "Thin Blue Line" was coined by Parker.[1][3] Parker's experience with the numerically larger force of his early career led him to judge that fewer but more professional officers would mean less corruption. Additionally, the strategy of changing the beat posture to one of mobility led to change from foot patrols to one which favored police cars. Not incidentally, this also furthered Parker's belief that isolating his officers from the streets would reduce opportunities for corruption. However, Parker recognized that certain areas of the city and certain functions of the police department needed to remain rooted in the more traditional form of police work.[1]

Although Parker reduced police corruption and cleaned up the overall image of the police, certain sections of the police continued practices which lent more to an image of old semi-corrupt control of vice and petty crime. The vice squad and reserve force continued to remain controversial elements of the police force. Parker also used elements of the reserve force such as the Organized Crime and Intelligence Division of the LAPD to keep tabs on suspected politicians and their mafia syndicate allies as well as the notoriously corrupt and narcotic ridden Hollywood movie industry system and its celebrities.[1] The 1990 novel and 1997 film L.A. Confidential along with the 2013 film Gangster Squad provide fictional depictions of the LAPD under Parker during these years.

Donovan, John T. (2005), "'I Have No Use For This Fellow Parker': William H. Parker of the LAPD and His Feud With J. Edgar Hoover and the FBI", Southern California Quarterly87 (2): 171–198, doi:10.2307/41172260